The present invention pertains to a tilting pin mechanism for the clamping device of a motor vehicle steering column, whose position can be adjusted, for detachably fixing a housing accommodating the steering column at a bracket that is a rigid part of the body, wherein the housing and the bracket have at least one cooperating friction surface pair that can be pressed against each other by means of the tilting pin mechanism, with a centrally arranged bolt which is displaceable in the direction of its central longitudinal axis and with at least one tilting pin having a longitudinal axis arranged approximately in parallel to the central longitudinal axis of the bolt.
Such a tilting pin mechanism is present, e.g., to build up the clamping forces in a clamping device corresponding to DE 44 00 306 A1. This specification discloses a clamping device, by which a housing accommodating the steering column is in contact with a bracket that is a rigid part of the body in the clamped state with corresponding friction surfaces. The clamping forces are built up by means of a plurality of tilting pins, which are supported with one end in an abutment at the housing and with their other end in an abutment at a bolt collar. The rotation of the bolt in one direction causes that the tilting pins can be brought into a locking stop position beyond an axial extended position in parallel to the axis of the bolt, in which stop position the necessary pressing forces are applied for the friction surfaces arranged between the bracket, which is a rigid part of the body, and the housing. During the rotation of the bolt in the opposite direction, the tilting pins come into a release position, in which the clamping connection is abolished and in which the tilting pins are sloped at a small angle in relation to the longitudinal axis of the bolt.
The clamping device described in the above-mentioned document, using a tilting pin mechanism, has proved, in principle, to be successful, but it has certain drawbacks, especially in regard to increased requirements on the clamping action. These are especially that the clamping path, i.e., the travel performed by the tilting pins from their release position into the locking position, is relatively short. In addition, due to the fact that the position of the tilting pin passes over beyond the axial extended position into a locking position, some of the theoretically existing clamping path, which is short anyway, is lost due to the fact that the tilting pins are held in the stable locking position. The fact that an abutment, e.g., in the form of an axial needle bearing, which permits the rotary movement of the actuating element to tilt off the tilting pin under force, is necessary for the tilting pin mechanism in question in the existing state of the art, has turned out to be another drawback.
The object of the present invention is therefore to improve a tilting pin mechanism of the type described in the introduction, such that longer clamping paths can be obtained. In addition, the mechanism according to the present invention shall have compact dimensions, it shall have a simple design and be inexpensive to manufacture.
According to the invention, a tilting pin mechanism is provided, preferably for the clamping device of a motor vehicle steering column, whose position is adjustable, for detachably fixing a housing accommodating the steering column at a bracket that is a rigid part of the body. The housing and the bracket have at least one cooperating friction surface pair that can be pressed against each other by means of the tilting pin mechanism. The tilting pin mechanism includes a centrally arranged bolt which is displaceable in the direction of its central longitudinal axis and with at least one tilting pin whose longitudinal axis is arranged approximately in parallel to the central longitudinal axis of the bolt. The tilting pin is supported on one side directly or indirectly at a bolt collar and is accommodated at its other end in a recess on the front side of an actuating ring. The tilting pin can be tilted into a lockable stop position and in the opposite direction into a release position by rotating the actuating ring beyond the axial extended position in parallel to the central longitudinal axis of the bolt. The actuating ring has at least one recess for an additional tilting pin on the second front side facing away from the first tilting pin. The other end of this tilting pin is supported in a thrust washer that is axially displaceable in the direction of the central axis of the actuating ring.
According to this technical teaching, the actuating ring, which brings about the tilting off of the tilting pins fitted in between the actuating ring and a bolt collar during rotation, has at least one recess for an additional tilting pin on the second front side facing away from the first-named tilting pins, wherein the other end of this additional tilting pin is supported in a thrust washer that is axially displaceable in the direction of the central axis of the actuating ring.
Due to this design according to the present invention, rotation of the actuating ring brings about a bilateral lifting movement of the tilting pins mounted in the front sides of the actuating ring. The travel can thus be doubled compared with the tilting pin mechanisms known from the state of the art. Since the recesses for the tilting pin or for the tilting pins arranged in both front sides are arranged offset in relation to one another, the mechanism according to the present invention has extremely compact dimensions despite the doubling of the travel.
It proved to be particularly advantageous to arrange two mounts so as to be offset by 180xc2x0 in relation to one another for one tilting pin each at each of the two front sides of the actuating ring. The mounts at one front side are arranged offset by 90xc2x0 in relation to those of the other front side. The bilaterally offset arrangement of the needle pairs stabilizes the middle actuating ring, as a result of which the number of tilting pins, which is usually three, can be reduced, which simplifies the manufacture and the assembly.
Moreover, provisions are made in another advantageous embodiment of the subject of the present invention that only two of the tilting pins present are in the xe2x80x9cover-the-dead-center position,xe2x80x9d i.e., beyond the axial extended position in parallel to the central longitudinal axis of the bolt, in the lockable stop position of the actuating ring, whereas the other two tilting pins are arranged exactly in the axial extended position. Due to the different arrangement of the tilting pins in the locking position, the clamping path can be additionally increased and the clamping action of the entire mechanism can thus be increased.
The rotation of the actuating ring can be brought about by coupling the actuating ring with a hand lever.